The invention relates to a method and a device for navigational assistance to a vehicle driver who is issued instructions which are derived from a comparison of a route, prescribed by route reference points, and respectively determined positions of the vehicle.
Systems for assisting the navigation of vehicles have become known in which after inputting the start point and destination this information is transmitted from a vehicle unit into a fixed computer (traffic computer). There, a digital map base is used to determine a route between the start point and destination. This route is transmitted to the vehicle unit in the form of a list of route reference points. Data are also transmitted on the route reference points, in particular the type of the route reference point, for example an intersection, a junction, a rotary intersection. Finally, the distances between the route reference points are transmitted to the vehicle unit. These systems are also known as off-board navigation systems.
In the known systems, the guidance information is transmitted to the driver in the form of symbolized representations of the guidepoints, especially the intersections and junctions. The vehicle driver lacks any information on the next segment of the roadway. He must therefore put his complete trust in the functionability of the system. Furthermore, imprecise calculation of vehicle position and complex street segments can cause the vehicle driver to change lanes rapidly when this is not necessary.